[23_21] Ban jump in text/math at of graphics area

TeXmacs/progs/graphics/graphics-kbd.scm

@@ -34,10 +34,6 @@
 (define (inside-graphics-context? t)
   (tree-search-upwards t graphics-context?))
 
-(define (inside-graphical-text-context? t)
-  (and-with p (tree-ref t :up)
-    (and-with u (tree-search-upwards p graphical-text-context?)
-      (inside-graphics-context? u))))
 
 (tm-define (generic-context? t)
   (:require (inside-graphics-context? t))
@@ -200,14 +196,12 @@
 (tm-define (kbd-horizontal t forwards?)
   (:require (graphical-text-context? t))
   (with-define (move) ((if forwards? go-right go-left))
-    (with-define (next) (go-to-next-inside move inside-graphics-context?)
-      (go-to-next-such-that next inside-graphical-text-context?))))
+    (go-to-next-inside move (lambda (t2) (equal? t (tree-ref t2 :up))))))
 
 (tm-define (kbd-vertical t downwards?)
   (:require (graphical-text-context? t))
   (with-define (move) ((if downwards? go-down go-up))
-    (with-define (next) (go-to-next-inside move inside-graphics-context?)
-      (go-to-next-such-that next inside-graphical-text-context?))))
+    (go-to-next-inside move (lambda (t2) (equal? t (tree-ref t2 :up))))))
 
 (tm-define (kbd-extremal t forwards?)
   (:require (graphical-text-context? t))